This invention relates to a method by which electronic equipment is remote-controlled, and more particularly to a circuit for receiving a remote-control signal consisting of a radio wave, an infrared wave, or a wave of some other medium.
A remote-control signal to control electronic equipment is generally transmitted from a remote transmitter, and is received at a receiver incorporated in the equipment to be controlled. The received remote-control signal is then decoded into a series of data values in order to identify the equipment to be controlled and the type of operation commanded by the remote-control signal.
This series of operations is generally performed by a micro-computer provided in the receiver. The micro-computer is equipped with an input terminal dedicated to receive the remote-control signal, and the signal is incorporated in the micro-computer by means of interruption processes.
In a control system, the remote-control signal consists of pulse trains, and the interruption process is triggered upon detecting the very first edge of the received pulses. After this, the remote control data are successively incorporated into the micro-computer while the widths of remote-control pulses are determined by means of a timer means.
In another control system, typical predetermined patterns of the remote control pulses are stored in the micro-computer, and the interruption process is automatically triggered to start the interruption process when the pattern of the received pulse train is found to be identical with one of the stored patterns.
However, as in the case of conventional remote controllers, when the remote control pulses consist of a series of remote control codes repeated at fixed intervals, the received remote-control signal inevitably contains data blank periods between the repeated data trains. Therefore, the data incorporating circuit stays in an active state even when the circuit is in the data blank period. Thus, the chances of mis-operation caused by an external random noise occurring in the data blank period are high with this circuit construction.
Moreover, with the interruption process employed in most of the systems incorporating the remote-control data into the micro-computer, a delay of the system operation is inevitable when the frequency of the interruption process is excessively increased.